The present application relates to gasket manufacturing apparatus and processes. More particularly, the present invention is directed to apparatus and methods for manufacturing rubber spiral wound gaskets.
Spiral wound gaskets made of rubber-derivative materials are used typically for oil seal connections in industrial processing applications. The rubber-based spiral wound gaskets are typically formed by rolling a thin sheet of rubber material in overlapping relation to form a tube. The overlapping layers of the rubber sheet define the radially-thick gasket having an inner diameter and an outer diameter for being received in a sealing application. A cross-section is cut through the tube to form a disc-like gasket of a selected thickness, having the selected inner diameter and outer diameter. The disc is pressed in a mold having an inner and outer diameter lip material for sealing. A primer encapsulates the windings of the rubber material with the lip material.
While these processes have resulted in rubber-based gaskets suitable for oil sealing and other applications, there are drawbacks to the apparatus and methods of manufacturing such gaskets. It is cumbersome to hold the sheet while rollingly winding the sheet into a tube. The tube must be held rolled while gaskets are cut, and the cut gaskets also must be held from unwinding. Further, the tube often can not be completely cut to form gaskets. The ends loosen and generally a portion of the tube must be scrapped.
Accordingly, there is a need in the art for an improved method and apparatus for manufacture for rubber-based spiral wound gaskets. It to such that the present invention is directed.
The present invention provides an apparatus and method for manufacturing rubber-based spiral wound gaskets. The apparatus for making a spiral wound gasket comprises a feeder that communicates a length of an elongate band for winding in overlapping relation to make a spiral wound gasket. The elongate band passes through a fluidial bath of a sealing material whereby the elongate band becomes enclosed within a jacket of the sealing material. A rotatable die defining a slot extending inwardly from a perimeter of the die receives a distal end portion of the elongate band, for winding around the perimeter of the die a length of the elongate band including the jacketed portion thereof. The apparatus provides a fixing device for securing selected portions of the wound elongate band together and a cutter for severing the elongate band, whereby the spiral wound gasket made with the length of the elongate band is separable from the apparatus. A tapper movable from a first position in alignment with a perimeter portion of the die to a second position striking forcibly against the perimeter portion of the die selectively dislodges the spiral wound gasket. The elongate band, being engaged to the die by the distal end portion of the elongate band being received in the slot, is wound around the perimeter of the die until a desired radially thick spiral wound gasket is formed and upon being secured together by the fixing device, the cutter operating to sever the elongate band and the tapper striking the perimeter portion of the die to dislodge the spiral wound gasket therefrom.
In another aspect, the present invention provides a method for manufacturing a rubber-based spiral wound gasket, comprising the steps of:
(a) receiving in a slot extending inwardly from a perimeter edge of a die a distal end portion of an elongate band having at least a length portion jacketed by a rubbery sealing material;
(b) winding a length of the jacketed elongate band around the perimeter of the die; and
(c) fixing selected portions of the wound elongate band together to form a rubber based spiral wound gasket.